Share-based compensation - Options (Details) - $ / shares |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2020 |
Jun. 30, 2019 |
Jun. 30, 2020 |
Jun. 30, 2019 |
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| Share-based compensation | ||||
| Number of options granted (in shares) | 2,738,936 | 936,696 | 12,968,216 | 11,743,896 |
| Weighted average fair value (in dollars per share) | $ 0.30 | $ 0.39 | $ 0.47 | $ 0.54 |
| Number of additional options with a nominal exercise price granted | 778,120 | 459,240 | 6,838,816 | 6,957,366 |
| Weighted average fair value of RSU-style options granted | $ 0.43 | $ 0.70 | $ 0.71 | $ 0.93 |
| X | ||||||||||
- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the nominal exercise price. No definition available.
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- Definition Gross number of share options (or share units) granted with nominal exercise price during the period. No definition available.
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- References No definition available.
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- Definition Gross number of share options (or share units) granted during the period. No definition available.
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- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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